Purpose
Ccl2/Cx3cr1double deficient mouse on rd8 background (DKO/rd8) is a model of focal retinal degeneration, which develops age-related macular degeneration (AMD)-like characteristics, such as progressive focal photoreceptor degeneration and atrophy, elevated A2E, and elevated expression of inflammatory cytokines and chemokines. The retinal dystrophy of DKO/rd8 was found to be associated with crumbs-like 1 (Crb1) gene mutation (Crb1rd8). This study investigated retinal phenotype and gene expression profiles on Ccl2-/-/Cx3cr1-/- , Ccl2-/-, Cx3cr1-/- three mouse strains with or without Crb1rd8.
Methods
Eight mouse strains with different genetic background were yielded via backcross of DKO/rd8 (Ccl2-/-/Cx3cr1-/-/Crb1rd8) with C57/J (Ccl2+/+/Cx3cr1+/+) or C57/N (Ccl2+/+/Cx3cr1+/+/Crb1rd8) mice. Funduscopy was performed before harvesting the eyes. RNA was isolated from ocular tissue of 4 months old mice. RT-PCR of IL-1β, IFN-γ, TNF-α, IL-17a, IL-18, NLRP3, Cxcl11, IL-22 and Ccl22 genes was performed. The mouse universal RNA was used for normalization.
Results
Funduscopy showed multiple retinal lesions in all mice with Crb1rd8. The retinal lesions in the mice with Crb1rd8 was most severe in DKO/rd8, followed by co-existing with Ccl2-/-or Cx3cr1-/-, and least in C57BL/6N. There were only few lesions in Ccl2-/-/Cx3cr1-/- but not in other mouse stains without Crb1rd8. The gene expressions show in table (table attached below). The higher expressions of all genes except Ccl22 were found in Ccl2-/-/Cx3cr1-/-/Crb1rd8 mouse than that in other strains.
Conclusions
Crb1rd8 mutation plays a critical role in the development of retinal lesions of the stains examined in this study. The deficiency of both Ccl2 and Cx3cr1 genes enhance the expressions of inflammatory molecules and may influence the severity of AMD-like retinal lesions.
Keywords: 494 degenerations/dystrophies •
490 cytokines/chemokines •
533 gene/expression